Automatic washing machine having means to measure the rate of change of turbidity



Dec. 17, 1963 E. Di MOREY ETAL 3,114,253

AUTOMATIC WASHING MACHINE HAVING MEANS TO MEASURE THE RATE OF CHANGE OFTURBIDITY Filed Sept. 13, 1962 5 Sheets-Sheet 1 m S R 3 s 4 z T W M o n4 4 1 7 M m a 9 2 6 R I 1 0 L O 9 5 6 6 mm WW H HH I I H MH 4. .w m... mA i+ SW 4 a M o A A 0 mm 0 E O 3 R w 6 6 o o 0 Z o o o 4 3 Av S o o o oo o z ml 4 o o o o 3 B o o o o o 2 W o W 4 2 8 A 2 u 3 F m I G I l H r m7 3 F s x o o m .S 2 J1 o o 2 2 l I o o o 4 5 o o o i 9 3 3 o 0 Z f s o3 e m I 0 2 F .mL F o o 6 l I v 4 S 2 2 In 1\ m Q. A M :1 5

THE\R ATTORNEY Dec. 17, 1963 E. D. MOREY ETAL 3,114,253

AUTOMATIC WASHING MACHINE HAVING MEANS To MEASURE THE RATE OF CHANGE OFTURBIDITY Filed Sept. 13, 1962 3 Sheets-Sheet 2 INVENTORS EVERETT o.MOREY BY OPOLDWZUBW THEIR ATTORNEY E. D. MOREY ETAL WAS Dec. 17, 19633,114,253

AUTOMATIC HING MACHINE HAVING MEANS TO MEASURE THE RATE OF CHANGE OFTURBIDITY 1962 3 Sheets-Sheet 3 Filed Sept. 13,

PAUS E A FIGS I ll :4 ma 3 TIME. (aosecauus) F'lG.6

TlME (seconbs) F'IG.'7

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TIME (MINUTES) THEIR ATTORNEY United States Patent 3,114,253 AUTOMATICWASHING MAQHENE HAVHNG MEANS TG MEASURE THE RATE GF CHANGE OF TURBTDITYEverett D. Morey and Leopold Loch, Louisville, Ky, assiwors to GeneralElectric (Iompany, a corporation of New York Filed Sept. 13, 1962, Ser.No. 223,312 9 Claims. (CI. 68-12) This invention relates to automaticwashing machines, and more particularly to such machines which includestructure responsive to the rate of change of turbidity of the liquidused in such machines.

In automatic Washing machines available at the present time, the washingoperation, as Well as all other operations, is a timed function. Inother words, the operator estimates how long it will take for articlesto get clean and sets the machine accordingly. As a result the machineproceeds to wash the articles by relative motion of the articles and theliquid for the predetermined time. In clothes washing machines, forinstance, this involves an estimate of the size of the clothes load, thetype of fabric, the type and amount of soil, the difliculty of removingsuch soil from that type of fabric, erficiency of the washing solution,and other such factors; with so many factors, it is virtually impossibleto estimate the needed time with accuracy.

A much more satisfactory solution is to cause an operation to beterminated when appropriate measurements show that it has beensuccessfully completed. In the case of clothes, this would means thatthe clothes would continue to be washed as long as the washing washaving a beneficial effect, and that as soon as further washing ceasedto have any advantage, the washing operation would cease and the machinewould then proceed through the remainder of its cycle.

It has long been known that, with a particular type of article having aparticular amount of soil, and with a known type of washing solutionpresent in a predetermined amount, the amount of soil extracted from thearticles may be measured by the turbidity, or cloudiness, or the liquidwashing medium. However, for practical purposes in appliances such asclothes washers, this does not represent an adequate solution to theproblem because of all the varying factors.

It is, accordingly, an object of our invention to provide an improvedmeans for automatically terminating an operation in a Washing machineonce said operation has been successfully completed.

A further, more specific, object of our invention is to achieve thisgoal by utilizing the turbidity phenomenon in a novel manner.

Specifically, it is an object of our invention to utilize the rate ofchange of turbidity to indicate what is happening in the machine and theneed for one type of controlling action or the other.

In one aspect of our invention, for instance, we provide a Washingmachine which has, in the usual way, container means for articles to bewashed and the liquid, together with suitable means for providing thearticles and the liquid with relative motion to each other. As animportant feature of our invention we provide means for measuring therate of change of turbidity of the liquid. When a predetermined rate ofchange is reached, it causes operation of control means which theneffects a suitable change in the condition of the washing machine.

As a specific example, in the washing of clothes the detergent solutionordinarily used will have an increas ing turbidity until soil ceases tobe removed from the clothes. At this point, the turbidity of the washsolution will cease to change and will remain fairly constant.

Accordingly, if the control means is actuated when the rate of change ofturbidity of the solution almost approaches zero, full effectiveness ofthe macldne in a minimum amount of time will be insured insofar as thewashing of all clothes is concerned.

The subject matter which we regard as'our invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. The invention itself, however, both as to itsorganization and method of operation, together with further advantagesthereof, may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings.

in the drawings, FIGURE 1 is a side elevational view of a clotheswashing machine which includes our invention, the View being partiallybroken away and partially in section to illustrate details;

FIGURE 2 is a View along line 2-2 in FIGURE 1;

FIGURE 3 is a schematic diagram of an electric control circuit includingour invention, which circuit is incorporated in the machine of FIGURE 1;

FIGURE 4 is a schematic View of a development of the cam surfaces usedin the control of the main timer operated switches of FIGURE 3, therebyindicating the operation of the switches by the cams throughout a cycle;

FIGURE 5 is a schematic view of a development of the cam surface of theauxiliary timer cam surface used in the control of the switches in theturbidity measuring portion of the circuit of FIGURE 3;

FIGURE 6 is a graph showing the voltage differential phenomenon,provided by the circuit of FIGURE 3 and which is utilized to sense therate of change of turbidity; and

FIGURE 7 is a graph showing a typical curve of the rate of change ofturbidity for a washing solution in the clothes Washing machine ofFIGURE 1.

Referring now to FIGURE 1, we have shown therein an agitator typeclothes washing machine 1 having a conventional basket or clothesreceiving receptacle 2 provided over its side and bottom Walls Withperforations 3 and disposed within an outer imperforate tub or casing 4;which serves as a liquid recs tacle, the basket and together serving ineffect as container means for clothes and the liquid in which they areto be washed and rinsed. Basket 2 may be provided with a suitableclothes retaining member 5 for preventing clothes from being floatedover the top of the basket and with a balance ring 6 to help steady thebasket when (as will be explained) it is rotated at high speed.

Tub 4 is rigidly mounted Within an appearance cabinet 7 which includes acover 8 hingedly mounted on the top portion 9 of the cabinet forproviding access to an opening it) to the basket 2. A gasket 11 may beprovided so as to form a seal between the top of tub d and portion 9 ofthe cabinet thereby to prevent escape of moisture and moist air into thecabinet around the tub. The rigid mounting of tub 4 Within the cabinet'7 may be eifected by any suitable means. As a particular example of onesuch means we have provided strap members 12, each of which is securedat one end to an inturned flange 13 of the cabinet and at its other endto the outside of tub 4. At the center of basket 2 there is positioned avertical axis agitator 14 which includes a center post 15 and aplurality of curved water circulating vanes 16 joined at their lowerends by an outwardly flared skirt 17.

Both the clothes basket 2 and the agitator 14 are rotat ably mounted.The basket is mounted on a flange 18 of a rotatable hub 19, and theagitator 14 is mounted on a shaft (not shown) which extends upwardlythrough the hub 19 and through the center post 15 and is secured to theagitator so as to drive it. During the cycle of operation of the machine1, water is introduced into the tub 4 and basket 2, and the agitator 14is then oscillated back and forth on its axis, that is, in a horizontalplane Within the basket. This causes washing of the clothes by effectingrelative motion of the clothes to the liquid, as well as suitableflexing of the fabric of the clothes. Then, after a predetermined periodof this washing action, basket 2 is rotated at high speed to extractcentrifugally the washing liquid from the clothes and discharge it todrain. Following this extraction operation, clean water is introducedinto the basket for rinsing the clothes and the agitator is againoscillated. Finally, the basket is once more rotated at high speed toextract the rinse water.

Basket 2 and agitator 14 may be driven through any suitable means from areversing motor. By way of example, we have shown them as driven from areversible motor through a system including a clutch 21. mounted on themotor shaft. A suitable belt 22 transmits power from clutch 21 to atransmission assembly 23 through a pulley 24. Thus, depending upon thedirection of motor rotation, pulley 24 of transmission 23 is driven inopposite directions. The transmission 23 is so arranged that it supportsand drives both the agitator drive shaft and basket mounting hub 19.When motor 2% is rotated in one direction the transmission causesagitator 14 to oscillate in a substantially horizontal plane within thebasket 2. Conversely, when motor Ztl is driven in the oppositedirection, the transmission rotates the wash basket 2 and agitator 14together at high speed for centrifugal liquid extraction. While thespecific type of transmission mechanism used does not form part of ourinvention, reference is made to Patent 2,844,225 issued to James R.Hubbard, et al. on July 22, 1958 and owned by the General ElectricCompany, assignee of the present invention. That patent discloses indetail the structural characteristics of a transmission suitable for usein the illustrated machine.

In addition to operating the transmission 23 as described, motor 24)also provides a direct drive through a flexible coupling 25 to a pumpstructure generally indicated at 26 which may include two separatepumping units 27 and 28 both operated simultaneously in the samedirection by motor 20. Pump 27 has an inlet which is connected by aconduit 29 to an opening 3% formed at the lowermost point of tub 4. Pump2'7 also has an outlet which is connected by a conduit 31 to a suitabledrain (not shown). Pump 23 has an inlet connected by a conduit 32 to theinterior of tube 4 and an outlet connected by a conduit 33 to a nozzle34. The pumps are formed so that in the spin direction of motor rotationpump 27 will draw in liquid from opening 30 through conduit 29 and thendischarge it through conduit 31 to drain, and in the other direction ofrotation pump 28 will draw in liquid through conduit 32 and discharge itthrough conduit 33 and nozzle 34, each of the pumps being substantiallyinoperative in the direction of rotation in which it is not used.

Nozzle 34 is positioned to discharge into a filter pan 35 secured on thetop portion 36 of agitator 14 so to be movable therewith. With thisstructure then, when the motor is rotating so as to provide agitationpump 2-3 draws liquid through conduit 32 from tub 4 and discharges itthrough conduit 33 so that the liquid passes from nozzle 34 into filterpan 35, and then down through a number of small openings 37 provided inthe bottom of the filter pan and back into basket 2. In this manner, thefilter pan 35 with its small openings 37 and its upstanding side wall 33causes lint which is separated from the clothes during a washingoperation to be filtered out of the water, and thus prevents it frombeing redeposited on the clothes. This type of structure is more fullydescribed and claimed in Patent 2,481,979 issued to Russell H. Colley onSeptember 13, 1949 and assigned to General Electric Company, owner ofthe present invention.

The motor 20, clutch 21, transmission 23, basket 2 and agitator 14 forma suspended washing and centrifuging system which is supported by thestationary structure of the machine so as to permit isolation ofvibrations from the stationary structure. It will be understood thatsuch vibrations occur primarily as a result of high speed spinning ofbasket 2 and the load of clothes therein, as mentioned above. While anysuitable suspension structure may be used, one suitable structureincludes a bracket member 3 with transmission 23 mounted on top thereofand motor 26 mounted to the underside thereof. The bracket member inturn is secured to upwardly extending rigid members 46*, and each of thetwo upwardly extending members 40 is connected to a cable 41 supportedfrom the top of the machine. While only a portion of the suspensionsystem is shown in the drawing, such a vibration isolating system isfully described and claimed in Patent 2,987,190 issued on June 6, 1961to John Bochan and assigned to General Electric Company, assignee of thepresent invention.

In order to accommodate the movement which occurs between basket 2 andtub 4 without any danger of leakage between them, the stationary tub 4is joined to the upper part of transmission 23 by a flexible boot member42. Boot 42 may be of any suitable configuration, many of which areknown in the art, to permit relative motion of the parts to which it isjoined without leakage therebetween.

Hot and cold water may be supplied to the machine through conduits 43and 44 which are adapted to be connected respectively to sources of hotand cold water (not shown). Conduits 43 and 44 extend into aconventional mixing valve structure 45 having solenoids 46 and 47 sothat energization of solenoid 46 permits passage of hot water throughthe valve to a hose 48. Energization of solenoid 47 permits passage ofcold water through the valve and energization of both solenoids permitsmixing of hot and cold water in the valve and passage of warm water intohose 4%. Hose 48 has an outlet 49 positioned to discharge into basket 2so that when one or both of the solenoids 46 and 47 are energized waterpasses into basket 2 and tub 4.

The level to which water rises in the basket and tub may be controlledby any suitable liquid level sensing means. One typical arrangement fordoing this is to provide an opening 59 in the side of tub 4 adjacent thebottom thereof, the opening 50 being connected through a conduit 51 anda tube 52 to a conventional pressure sensitive switch (shownschematically in FIGURE 3 by the number 53) which may be positionedwithin the backsplasher 54 of machine 1. In the conventional manner, asthe water rises in basket 2 and tub 4 it exerts increasing pressure on acolumn of air trapped in tube 52, and at a predetermined pressure levelthe column of air then trips switch 53 to shut oil whichever ofsolenoids 45 and 47 may be energized. The backsplasher 5'4 may havesuitable manual controls, such as that shown at 55. Controls 55 are usedto control, for instance, washing and spin speeds,

water temperatures, water level within the tub 4 and basket, etc., forthe washing of different types of fabrics. It will be noted that, inaccordance with one aspect of our inventive concept, we provide anopening 56 in the wall of tub 4 (FIGURE 2). Opening 56 leads into anenclosure surrounded by a member 57 formed of transparent material suchas, for instance, glass or clear plastic. Member 57 may be securedthrough an appropriate sealing gasket 53 to the tub 4 so that itcooperates therewith to form a water tight connection. Also secured tothe tub wall 4 around member 47 is a support member 5'9. On one side 5%of member 57, member 59 supports a source of light 61, such as, forinstance, an ordinary incandescent light bulb. On the other side 62 ofmember 57 the member 59 supports a resistor 63 having conductors 64 and65 connected thereto, and appropriately insulated from member 59 asshown by insulating block 66.

Referring now to FIGURE 3 the electrical control system for the machineof FIGURE 1 will be described. In connection with the circuit of FIGURE3 it will be understood that present day Washers often include variousimprovements such as two speed mechanisms, control panel lights, bleachdispenser controls, etc., which do not relate to the present invention,and that, to some extent, these have been omitted for the sake ofsimplicity and ease of understanding.

In order to control the sequence of operations of the components ofmachine 1, the circuit includes a main automatic sequence controlassembly which incorporates a timer motor 67 driving a plurality of camscs, 69, 7d, 71 and 72. These cams, during their rotation by the timermotor, actuate various switches, as will be described, causing themachine to pass through an appropriate cycle of operations, firstwashing the clothes, next extracting water from them by centrifuging,then rinsing the clothes in clean water, and finally centrifuging therinse water from the clothes. The operating surfaces of the differentcams are shown in developed form in FIGURE 4- and will be furtherdiscussed herebelow in connection with the description of the operationof the machine. The electric circuit as a Whole is energized from apower supply (not shown) through a pair of conductors 73 and 7d. Cam (8controls a switch 75 which includes contacts 76, 77 and 78. When the camhas assumed the position where all three contacts are separated, machine1 is disconnected from the power source and is inoperative. Whenoperation of machine 1 is to be initiated, as will be explained below,switch 75 is controlled by cam 6-8 so that contacts 76 and 77 areengaged. When the main switch 79 is closed (by one of the controls 55),power is then provided to the control circuit of the machine fromconductor 73 through contacts 76 and 77.

From contact 77 the circuit extends through a conductor so and amanually operated switch 81 to the valve controlled solenoid 47. Inaddition, a circuit is completed from conductor 89 through a switch 82controlled by cam 69. In the up position shown, switch 82 completes a crcuit for solenoid 47 independently of switch 31, and in the downposition switch 82 completes a circuit for solenoid 46. Thus, whenswitch 81 is open energiza-tion of solenoids 46 and 4-7 is under thecontrol of switch 32, but when switch 81 is closed the cold watersolenoid 47 may be energized independently of the position of switch 82.

From the hot and cold water solenoids the energizing circuit thenextends through a conductor 83 and then through a coil $4 of a relay 85,the main winding as of motor 20, a conventional motor protector 87, aswitch 88 controlled by cam 71, switch 79, and the conductor 74. Motor29 is of the conventional type which is provided with a start Winding 89which assists the main winding 86 during starting of the motor and isenergized in parallel therewith. When a relatively high current passesthrough the relay coil 34, it causes the relay contact 9%) to be closed.This permits an energizing circuit for the start winding to be completedin parallel with the main winding through a contact 91 of a switchgenerally indicated at '92 and which is controlled by cam 7d, contactarm 93%, the relay contact 9%), start winding 89, contact arm 94, andcontact 95 of switch 9 2. A circuit is also completed in parallel withmotor Zil from conductor 83 through a switch A; controlled by cam 72,and then through the timer motor 67.

Relay coil 84 is designed to close contact 9% when a relatively highcurrent, of the level demanded by the motor when it is rotating below apredetermined speed, is passing through it. At other times, when thereis no current passing through the relay coil 84, or when the current isbelow the required energizing level as is true in the running speedrange of the motor, the contact 9t? is open.

When the main winding 86 of motor 26' is in series with the valvesolenoids 56 and 47 as described, a much lower impedance is presented inthe circuit by the motor 24 than is presented by the valve solenoids. Asa result, the greater portion of the supply voltage is taken up acrossthe solenoids and relatively little across the motor. This causeswhichever of the solenoids in connected in the circuit to be energizedsutficiently to open its associated water valve. As a result, water at aselected temperature is admitted to the machines through outlet 49*,motors 20 and 6'7 remaining inactive. This action continues with thecircuitry thus arranged, so that the water pours into the basket 2 andtub Because of the perforations 3 the water rises in both basket and tubat substantially the same rate. As the head or" water acting on thecolumn of air trapped in the tube 52 increases, the pressure of this airincreases until it actuates the switch 53 provided within thebacksplasher 54.

When switch 53 closes, it then provides a short circuit across thesolenoids directly from conductor to conductor 83 so that, with thesolenoids thus excluded from the effective circuit, they becomede-energized and a high potential drop is provided across winding as ofthe motor as. This causes the relay coil 84 to close contact and startthe motor 2% while at the same time motor 67 starts so as to initiatethe sequence of operations. It will thus be observed that theenergization of the valve solenoids 4e and 47 and the enengization ofthe drive motor 20 are alter-native in nature. In other words, whenthere is sutficient potential across the valve solenoids to energizethem, the motor remains de-energized, and it is necessary to short thesolenoids out of the circuit so that they are de-energized before thedrive motor can be energized.

It is to be observed that switch 88 is in series with the main motor 2t?but is not in series with the timing motor 67. Thus, by the opening ofthis switch, the operation of motor 2% is stopped. The timer motor maynonetheless continue to operate as a result of the fact that the timermotor 67 is deliberately provided with an impedance much greater thanthat of the valve solenoids so that it will take up most of the suppliedvoltage and will continue in operation, leaving so little voltage acrossthe solenoids that they do not operate their respective valves.

Our invention contemplates the use of switch '96 in series with timermotor 67, so that when cam 72 opens switch $6 the timer motor 67 may bede-energized, and the main motor 2% will nonetheless continue to opeuateindependently thereof. This particular feature and its purpose will befurther explained herebelow.

A further point of the circuit of FIGURE 3 is that when switch arms 93and 9 4 are moved by cam 70 to engage contact and a contact 97respectively, the polarity of the start winding is reversed. The circuitfrom conductor 83 then proceeds through contact 97, contact arm thestart winding 89, relay contact 96, contact arm 93 and contact 95 to theprotector device 37 and conductor 74-. Thus, provided motor 2t isstopped or slowed down so that relay contact 9t) is closed, the reversalof switch 2 is effective to cause the motor 217 to rotate in theopposite direction when the motor starts it up again.

In order to energize motor 20 independently of the water level switch 53and the valve solenoids, so that a spin operation may be providedwithout regard to the absence of a predetermined water level, cam 63 isformed so that it may close all three contacts 76, 77 and 78 of switch75 during centrifugal liquid extraction steps. When this occurs, itcauses the power to be supplied from conductor 73 directly throughcontact 78 to conductor 83 and the motors, rather than through the waterlevel switch or the valve solenoids.

It will be observed that the cam 72, as well as controlling switch 9'6,also controls a second switch 98 ganged to switch 96. When switch 96 isclosed, switch 98 is in engagement with a contact 99, and when switch 96is opened switch 98 is in engagement with a contact 1%. When switch 93engages contact 1%, it is efiective to energize an auxiliary timer motorassembly dill which amazes controls a cam 102. Cam 102 controls thecondition of a switch 163, in addition to other functions to behereinafter described; when contact arm 98 engages contact 99 and switch103 is closed, energization of the timer motor 101 may be completed justas if switch arm 93 engaged contact 190. However, if switch 163 is openthen engagement of contact arm 98 with contact 99 does not effectenergization of the timer assembly ltd.

Referring now to FIGURE 4 in conjunction with FIG- URES 1 and 3, asequence of operation of machine it will be described. It will beassumed tha the timer has been set at Wash so that cam 68 has causedcontacts 76 and 77 to be closed, cam 69 has moved switch S2 to its downposition, cam 79 has positioned switch 92 as shown, cam 71 has closedswitch 38, and cam 72 has closed switch 96 and moved switch 98 intoengagement with contact 99.

At this point, the first step which takes place is the filling of themachine with hot water by the energization of solenoid 46. If switch 81has con manually closed, solenoid 47 Will also be energized and coldwater will be provided as well as the hot water, to provide warm waterin the machine. The energization of the solenoids, as previouslyexplained, causes motors 2d and 67 to remain inactive, and this statuscontinues until the closure of switch 53, at a predetermined level, atwhich point the solenoids are de-energized and consequently motor 2t)and 67 are energized, the energization of motor 29 being in thedirection to cause an agitation operation (because of switch 92).

After a washing operation has started, the timer motor 67 will, after abrief period of operation, on the order of one minute or so, cause thecam 72 to open switch 96 and move switch 98 down into engagement withcontact 100 thereby to energize auxiliary timer assembly 101. As will beexplained herebelow, this then provides an automatic control for thewashing operation causing it to terminate when it has been completedrather than after some predetermined length of time. In effect, whathappens is that the timer motor is re-energized when it is sensed thatno further cleaning of the clothes is necessary, and then proceeds toterminate the wash operation by causing cam 71 to open switch 88.

This provides pause A by stopping operation of motor 20, andconsequently there is no further agitation although, as explained above,the timer motor 67 continues to operate. The operation of the timermotor is insured because, after the re-starting of the timer motor (aswill be explained herebelow) it causes cam 72 to re-close swtich 96 andreturn switch 93 into engagement with contact 99. During pause A, cam 69moves contact 82 to its up position, and cam 70 reverses the position ofthe contact arms of switch 92.. In addition, switch 68 closes the threecontacts 76, 77 and 73 of switch 75 so as to provide, in effect, adirect connection from line 73 to line 83, thereby by-passing thesolenoids 46 and 47.

The reversal of switch 92 reverses the polarity of start winding 89relative to main winding 81. As as a result, when, at the end of pauseA, switch 88 is closed by cam 71, motor 20 is energized once again butin the opposite direction. The energization of motor 20 and thecontinued state of deenergization of the valve solenoids results fromthe closure of all three contacts of switch 75, bypassing the solenoidsand causing the motor to be energized directly across the source ofpower. As a result, motor 26 starts to operate pump 27 to effect rapidremoval of water from tub 4.

In addition, the basket 2 is accelerated to a high rotational speedwhich effects centrifuging of liquid out of the clothes, so that asubstantial part of the washing solution is removed by the cooperativeaction of the spinning basket and the pump 27. The full rotational speedmay, for instance, be on the order of 600 rpm, a speed sufiicient toextract a very substantial part of the wash solution from the clothesfor removal by the pump 27. This spin operation continues until pause B,as shown in FIGURE 4-, at which time switch 83 it again opened by cam'71 to de-energize motor 20. At this time cam 68 returns switch to thewash position, with contact 73 disengaged from the other two contacts,and the motor connections are reversed to provide agitation rather thanspin action. The rinse operation, with cold water as a result of theposition of switch 82, then proceeds in the same manner as the washingoperation when switch 88 re-closes.

Then, at the end of the rinse operation, there is another pause Cprovided by the opening of switch 88, at which time the switches 75 and92 are returned to the position necessary for a spin operation to beprovided. When switch 88 re-closes, a second spin operation is provided,and at the end of this second spin operation all three contacts ofswitch 75 are separated to terminate the operation.

Having outlined the general operation of washing machine 1, the specificfeature which provides the use of our invention in the machine will bedescribed. In connection with this feature, the various components ofthe circuit provided for effecting the desired purpose will be setforth. In addition to controlling the switch 1&3, cam iii-2 alsocontrols a switch 194 and a switch 105. The time for assembly itll tocause a full rotation of cam N2 is relatively short, and may, forexample, be on the order of thirty seconds.

Viewing FIGURE 5, it can be seen that the switch 194 is in its downposition engaging a contact 166 during seconds three to six, and is inits up position engaging a contact 167 during seconds twenty-four totwenty-seven. The remainder of the time, this switch 104 is in a neutralposition between contacts 165 and 197. Switch can be seen to be closedonce for each revolution of cam M2 for a period of two seconds from thetwenty-eighth second to the thirtieth second. This insures, in elfect,that the closure of switch 105 occurs after both contacts 136 and 107have been engaged by contact arm 104-.

The switch 103 is closed from the second second through the thirtiethsecond of each rotation of cam 192. What this does, in effect, is toinsure that, whenever switch 93 is moved out of engagement with contact1% and up into engagement with contact 99 (except during the first twoseconds of the cycle of cam 102), the assembly 1521 will continue to beenergized through switch 103 until the end of a full cycle of cam 162,is reached; at that time, the opening of cam 1%? will provide for thedeenergization of assembly 101 with all three contacts 103, m4 and itsin the correct position for the initiation of another operation. This,as will appear below, is important to the successful operation of theparticular illustrated embodiment of our invention.

The entire turbidity sensing circuit generally indicated by the numeral1&8 is energized through a transformer Hi9 which has a primary windingconnected across conductors 80 and 74 so as to be energized across theconventional 110 volt source of alternating curent power. The secondarywinding 111 of transformer 169 thus provides an alternating currentvoltage across its ends. This current is rectified by a half waverectifier 112, and the fluctuations are somewhat smoothed out, in aconventional manner, by the provision of a capacitor 113 and a resistor114; these tend to provide for controlled discharge of the capacitorduring periods when the rectifier is preventing current from flowing,and thus result in a fluctuating direct current.

The lamp 61, previously referred to in FIGURE 2, is connected forenergization across this source of direct current power, preferably inseries with a resistor 115 so that a desired low voltage may be used forenergization of the lamp 61 Without affecting the voltage supply to theremainder of the sensing circuit.

When contact 1&4 is in its down position, as shown in engagement withcontact 106, a circuit for charging a 9 capacitor 116 is provided asfollows: Starting at the resistor lie, the circuit proceeds through thelight sensitive resistor 63, contact arm 104, contact 1%, a biasingresistor 117 (to be further discussed herebelow) the capacitor 115 andthen back to the other side or" the secondary winding ill. Thus, duringthe first three seconds of closure of switch 1'34 th re is charging ofcapacitor 116. In the same fashion, during the three seconds of closureof switch liltwith contact 2W7, there is charging of a capacitor Stillthrough a circuit which proceeds from resistors 114 and 63 through thecontact arm ltl i, contact 1 317, a biasing resistor 119 (also to behereinafter further discussed), the capacitor 113, and then back to theother side of secondary winding ill.

During the twenty-eighth and twenty-ninth seconds of a rotation of earn132 the switch 165 is closed and this completes an energizing circuitfor a glow tube 12% which is of the conventional type, that is, it issubstantially non-conductive until a certain voltage across it isreached, at which time it fires and emits light as long as there is anadequate voltage drop across it. When switch 1% is closed, a circuit forfiring the glow tube 124) is completed as follows: Starting from sidelZll of capacitor 116, the circuit proceeds to the glow tube, thenthrough the switch M5 to side 1222 of capacitor 118. What this means, ineffect, is that if the capacitors are not charged, or are charged thesame, there is no voltage across the glow tube, but if the capacitorsare charged to a substantially different extent, then upon closure ofswitch 105 there will be a voltage differential across the glow tube120, and when this differential is great enough the glow tube will fire.

When the glow tube 129 fires, it causes a light sensitive resistor 123,which is normally virtually non-conductive, to become conductive, andthis in turn permits energization of a relay coil 124, it beingunderstood that such firing always occurs during a washing operation ata time when switch 53 is closed so as to place the resistor 123 and coil124 across the conductors '73 and 74. Energization of coil lid closesthe two switch contacts 125 and 12s. The closure of contact 126 locksthe relay 124 in independently of resistor 123 so that even after theglow tube stops firing, and resistor 1'23 returns to a very highresistance, the relay 124 will continue to be energized.

This continued energization of relay 124 causes, through its closedcontact 125, energization of the timer 67 with which contact 125 is inseries. It is as a result of this that the timer starts to operateagain, as briefly mentioned hereabove, and then reclose switch as sothat the remainder of the timer operation is independent of the circuit1%.

Returning now to the circuit 1% to describe the manner in which itachieves its desired purpose, the capacitors 13 .6 and lid are sodesigned that for a given voltage across them, the capacitor 118 willcharge slightly faster than the capacitor 116. This may, of course, beachieved by the characteristics of the capacitors themselves, or by thelength of charging time as determined by cam 162, or, probably mosteasily, in the manner shown by providing appropriate resistors ll! andH9 in series respectively with the two capacitors and adjusted to obtainthe desired effect.

At this point it is desirable to refer to FIGURE 7 in which there isshown a typical rate or" change of turbidity of the washing solution intub 4 for a representative clothes load. it will be observed that theturbidity of the water changes, initially, at a relatively substantialrate as the result of the removal of soil from the fabrics and itsaddition to the washing solution. In other words, as the clothes arewashed and the soil is removed from them, the washing solution becomesmore and more cloudy.

This change continues at an appreciable rate, as shown by the relativelysteep part of the curve in FIGURE 7,

until the point is reached Where the amount of soil removed from theclothes becomes less and less, finally decreasing to virtually nothing.As this happens, th turbidity of the liquid ceases to change since thereis no further soil being added to the washing solution to cause anychange or" turbidity. In other words, a condition of the clothes inwhich no further soil is being removed from them can be determined fromthe fact that the turbidity has virtually ceased to change, as shown inFIGURE 7.

It is this phenomenon that is used to effect the desired purpose; whilethis may be done in various ways, the particular system includingcircuit 168 is shown as one representative means of achieving thedesired goal. What has been done is that the capacitors 116 and 113 areso calibrated that during a fairly rapid change in turbidity, as shownby the steep part of the curve in FIG- URE 7, they will charge atsubstantially the same rate even though for the same voltage thecapacitor 118 would charge faster. This results from the inclusion inthe circuit of the light sensitive resistor as which, as the turbidityincreases, receives less and less light from lamp 61 because of theincreasing cloudiness of the washing solution in tub 4.

In other words, durin the period of eighteen seconds from the time thatcapacitor lid ceases to be charged until capacitor lit-l starts to becharged, the resistance of resistor 63 increases due to the fact thatless light is reaching it, and therefore the voltage available to chargecapacitor 118 is less than that available to charge capacitor Illa.

Therefore, during a change of turbidity, after both capacitors have beencharged and the switch res closes, there is very little differencebetween voltages across them; consequently, there is virtually novoltage across the glow tube 12% and it does not fire. This can best beseen by reference to FIGURE 6. in that FEGURE, during seconds three,four and five capacitor lid charges as shown, and then very slowlydischarges a small amount during the next few seconds. This is primarilydue to the presence of a very high resistance 127 in parallel with thecapacitor; resistance 127 is provided to insure that the capacitor willbe discharged prior to the start of another washing operation so that itwill be fully eiiective to perform its measuring function. In otherwords, the resistor lZi is effective to discharge capacitor 116 over aperiod of about twenty minutes to one-half hour, but has a ver minoreffect on it in the few seconds which elapse between chargings of thecapacitor 1126 during a'washing operation. The same function,incidentally, is provided for capacitor ill? by a very high resistance12%.

As a result of the charging of both capacitors, at the twenty-eighthsecond when switch is closed the volt age across the first capacitor isa point on the curve V in PlGURE 6, while the voltage across the secondcapacitor is at a point on the curve V This is a very small voltagedifferential, and does not operate to fire glow tube 12h.

As long as the turbidity continues to increase as a result of soilremoval from the clothes, the capacitors continue to charge at about thesame rate and therefore the voltage across them at the time ofattempting to fire glow tube 12d remains very small. However, as therate of change of turbidity decreases because the removal of soil fromthe fabrics in the machine is slowing down. the change in resistor 63becomes less and less between the charging of capacitor lit; and thecharging of capacitor Elli. As a result, because capacitor lib has thepredetermined characteristic of charging faster than capacitor 116 for apredetermined voltage across it, the voltage differential between thetwo capacitors during the time of closure of switch rss increasesquickly until it reaches the level shown in FIGURE 6 as V 1 This differll ential of the voltages of capacitors 116 and 113 is sufficient to firethe glow tube 12%.

As a result, the glow tube is fired to cause conductivity of lightsensitive resistor 123, relay 124 is energized, and the timer motorclose its switch 96 and then open the oration very shortly thereafter.This is done by having the timer motor close its switch 96 and then openthe switch 88 as previously described. The closing of switch J6 alsomoves switch $55 into its up position and in engagement with contact 99.This ensures operation of the timer assembly 181 until the end of itscycle unless it is in the first two seconds of its cycle. lt will beseen that this is important since it is necessary for proper operationof the system disclosed that the capacitor 116 always be the first to becharged during a washing operation.

Broadly, what has been done is to determine that the rate of removal ofsoil from fabrics in a washing machine has a direct relationship to therate of change of turbidity of the washing solution, and to utilize thisknowledge to cause the washing operation to be terminated when the rateof change of turbidity approaches zero.

It will be recognized that while we have shown a particular arrangementfor achieving sensitivity to the rate of change of turbidity andproviding operation of a control member in response to it, our inventionis not restricted to the particular system shown. Rather, it encompassesbroadly systems designed to respond to the ate of change of turbidity ofany liquid washing medium in order to effect a control function when apredetermined rate of change is reached. It will further be recognizedthat while we have shown this in particular connection with a clotheswashing machine, it is readily conceivable that the washin of otherarticles may be made dependent upon the rate of change of turbidity ofthe washing solution. This is also true as to rinsing of articles whichneed to be rinsed such as, for instance, clothes, since the water willbecome turbid at a rapid rate during the early part of a rinseoperation, but only at a relatively slow rate, decreasing toward zero,as the effective removal of washing solution from the clothes decreases.

In addition, it is readily conceivable that other ways of utilizing therate of change of turbidity of a washing soiution may be found. Forinstance, in a machine which washes for a fixed length of time, smallamounts of detergent could be repeatedly added. With a lightly soiledload, the turbidity would rapidly reach a steady state and thereby givea signal to cease addition of detergent. With a heavily soiled load,detergent addition would continue for a longer period because theturbidity would continue to change for a longer period than in the caseof the lightly soiled load.

All of these are possibilities that readily come to mind as a result ofthe particular structure and concept disclosed hereaoove. Therefore, itwill be understood that while in accordance with the patent statutes wehave described what at present is considered to be the preferredembodiment of our invention, it will be obvious to those skilled in theart that various changes and modifications (such as, but notexclusively, those set forth above) may be made therein withoutdeparting from our invention, and it is therefore aimed in the appendedclaims to cover all such changes and modifications as fall within thetrue spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A washing machine comprising:

(a) container means for articles to be washed and a liquid;

([1) means for effecting relative motion of the articles and the liquid;

(6) means for measuring the rate of change of turbidity of the liquid;

((1) control means for elfecting a change in the condition of saidwashing machine;

(e) and means for operating said control means when said measuring meanssenses a predetermined rate of change of turbidity.

2. The apparatus defined in claim 1 wherein said means for measuring therate of change of turbidity of the liquid includes a source of lightpositioned so that lig t rays are caused to pass through a predeterminedthickness of the liquid, and a light-sensitive resistor positioned inspaced relation to said source of light so that the rays from the lighthave to traverse the liquid to reach it.

3. The apparatus defined in claim 2 wherein said container meansincludes a projection formed of transparent material, and said lightsource is positioned on one side of said projection outside saidcontainer means and said light sensitive resistor is positioned on theother side of said proiection outside said container means.

4. A washing machine comprising:

(a) container means for articles to be washed and a washing solution;

(b) means for effecting relative motion of the articles and the washingsolution;

(c) means for measuring the rate of change of turbidity of the washingsolution;

(d) means for terminating operation of said means for effecting relativemotion;

(e) control means for actuating said terminating means;

(f) and means for operating said control means when said measuring meanssenses a rate of change of turbidity decreasing toward zero.

5. The apparatus defined in claim 4 including means for renderinginoperative said means for operating said control means during a briefinitial period of operation of said means for effecting relative motion.

6. The apparatus defined in claim 4 wherein said washing machine is aclothes washer.

7. The apparatus donned in claim 6 wherein said container means includesa perforated inner container for retaining the clothes and animperforate outer container for retaining the liqui 8. The apparatusdefined in claim 6 wherein said control means is a timer assemblyeffective to cause the remainder of a clothes washing operation to beprovided after a washing step has been completed.

9. A washing machine comprising:

(a) container cans for articles to be washed and a liquid;

(b) means for effecting relative motion of the articles and the liquid;

() means for measuring the rate of change of turbidity of the liquidincluding a source of light positioned to send light rays through apredetermined thickness of the liquid, a light sensitive resistorpositioned in spaced relation to said source of light so that the raysfrom the light have to traverse said predetermined thickness of theliquid to reach it, and first and second capacitors and means foralternately charging said first and second capacitors in circuit withsaid resistor so that said resistor decreases the char,,- ing rate ofsaid capacitors as the turbidity of the liquid increases, said secondcapacitor charging a greater amount each time for the same predeterminedvoltage and approximately the same amount when a lower voltage isapplied across said second capacitor than across said first capacitor sothat said capacitors charge at approximately the same rate when theliquid turbidity is changing rapidly but becomes charged to anincreasingly differential degree as the rate of change of turbidityslows down;

(a?) control means for eifecting a change in the condition of saidwashing machine;

(e) and means for operating said control means when said measuring meanssenses a predetermined decrease in the rate of change of turbidity,comprising 3,114,253 13 v 14 a device operative upon a predeterminedvoltage References Cited in the file of this patent drop thereacross,and means for connecting said UNITED STATES PATENTS device across saidcapacitors after each charging of said first and second capacitors sothat said device 2,218,698 Clark 1940 operates when said capacitors arecharged to a pre- 5 2,361,235 Pick 24, 1944 determined differentialdegree. 2,430,668 Chamberlin Nov. 11, 1947

1. A WASHING MACHINE COMPRISING: (A) CONTAINER MEANS FOR ARTICLES TO BEWASHED AND A LIQUID; (B) MEANS FOR EFFECTING RELATIVE MOTION OF THEARTICLES AND THE LIQUID; (C) MEANS FOR MEASURING THE RATE OF CHANGE OFTURBIDITY OF THE LIQUID; (D) CONTROL MEANS FOR EFFECTING A CHANGE IN THECONDITION OF SAID WASHING MACHINE; (E) AND MEANS FOR OPERATING SAIDCONTROL MEANS WHEN SAID MEASURING MEANS SENSES A PREDETERMINED RATE OFCHANGE OF TURBIDITY.